Hydraulic safety valve



Patented Aug. 7, 1945 UNITED STATES PATENT o FFICE' HYDRAULIC SAFETYVALVE Rudolph H. Blank, Treadwell, N. Y. Application February 2, 1943,Serlal No. 474,457

1 Claim.

My invention relates to the distribution of liquids, gases and the liketo a. plurality of points from a single source of supply, and has amongits objects and advantages the provision of an improved automaticshut-oil valvedesigned to cut off that portion of the system in which aleak may occur to prevent complete failure of the entire system bycontinued loss of the liquid or as. While the invention is suitable foruse in various types of fluid distributing systems employing multipledelivery from one source of supply, the invention is particularlysuitable for use in connection with the hydraulic braking systems ofautomotive vehicles. The safety valve is set in operation through theinfluence of pressure differentials, as between the difierence inpressures between the broken and unbroken portions of the system.

In the accompanying drawing:

Figure 1 is a diagrammatic plan view of a hydraulic braking system ofthe four wheel type illustrating two valves incorporated therein.

Figure 2 is a similar view employing one valve.

Figure 3 is a sectional view of the valve, and

Figure 4 is a sectional view along the line 44 of Figure 3.

In the embodiment of the invention selected for illustration, Figure 3illustrates a'valve body lll provided with bosses l2, l4, I6 and I8. Thebosses I2 and [4 are coaxial and the bosses l6 and I8 are also coaxialone with the other but with their common axis arranged at right anglesto the common axis of the bosses l2 and I4 In an installation accordingto Figure l, the boss 12 is connected with a brake line through themedium of a compression nut 22 threaded into the threaded bore 24 of theboss l2. The brake lines 24 leading to the front wheel brake units 26are respectively connected with the bosses I6 and I8 through the mediumof compression nuts 28 threaded into the threaded bores 30 of thebosses.

The brake lines 32 leading to the rear wheel brake units 34 arerespectively connected with the bosses l6 and 18 of a second valve unitidentical with that of Figure 3, while the boss l2 of this valve unit isconnected with a brake line 36. The two brake lines 20 and 36 havecommunication with a brake line 38 leading to a master cylinder 40 ofthe hydraulic braking system. Such master cylinders and their operationare well known in the art. The installation of Figure 2 differs fromthat of Figure 1 in that one valve unit only is employed, which valveunit is interposed in the brake line 42 leading to the front and rearbrake fluid distributing lines ,44 and 46, respectively. The boss [2 inthe installation of Figure 2 connects with a brake line 48 leading tothe master cylinder 50.

The valve body I0 is provided with a chamber '52 having a wall 54provided with two ports 56 communicating with a bore 58 coaxial with thebosses l6 and I8. Adapters 60 are threaded into the bores 38 forcompressing rubber washers 62 against annular shoulders 64 in the .valvebody I. Both washers 62 have original inside diameters equal to that ofthe bore 58 and are compressed to constrict the inside diametersslightly and to provide rounded faces 64'.

Each adapter 60 is provided with a fluid passage 66 and a valve seat 68.Both adapters are also provided with conical faces 10 coacting with theflared connections of the compression nuts, not shown. Such connectionsare old and 'well known in the art and need not be described in furtherdetail.

Inside the bore 58 is mounted a ball valve element l2. This valve isnormally seated on the concaved face 14 of a pin 16 slidable freelyin abore 18 in the valve body l2. This bore is arranged at right angles tothe axis of the bore 58 and is located equal distances from the twovalve faces 68. The pin 76 is yieldingly urged against the element 12 bya compression spring 80 mounted in the bore 82 of the pin 16. Thus theelement 12 is pressed against the face of the bore 58 to be releasablysupported against accidental displacement. The element '12 may bevdisplaced from its seat 14 only through a predetermined unbalanced fluidpressure condition on opposite sides of the element.

Ports 56 respectively communicate with the bore 58 on opposite sides ofthe element 12. A bore 84 is provided in the valve body l0 for thereception of a rubber washer 86 having an inside diameter looselyhousing a flange 88 on the pin 16. An adjusting screw 90 is threadedinto a bore 92 coaxial with the bore 84 and engages the washer 86. Thespring abuts the screw and the tension of the spring may be variedthrough adjustment of the screw, the latter being provided with a slot94 for the reception of a screw driver.

A rubber sealing washer 96 lies against the screw 90 and is engaged by ascrew plug 98 threaded into a bore "10 in the boss l4. Thus the boss l4provides a sealed condition against the escape of fluid or gases underpressurein the valve body.

The adapters 60 include bores I02 having diameters permitting theelement I2 to move freely therein for engagement with the valve faces'8, although the washers I: offer some resistance to passage of theelement into the bores. However, the element 12 is held against theengaging valve face 88 by the adjacent washer 62 after the element hasbeen pressed through the washer.

Under normal operating conditions, the fluid or gas under pressure fromits source of supply passes through the adapter II in the boss I 2,enters the chamber I2 and passes through the ports is for delivery tothe bore It on opposite sides of the element 12. The fluid then passesthrough the adapter '0 in the bosses l8 and It for delivery to'thepoints of application. In a hydraulic braking system under normalconditions, the fluid under pressure exerts an equal pressure throughoutthe entire system. Thus the pressures effective on the element 12 areequal and the element remains in its normal full line position of Figure3.

When the normal condition is changed, the pressures effective on theelement 12 become unbalanced and the element is caused to move in thedirection of the low pressure side of the valve. Figure 3 illustratesthe valve 12 in dotted lines and in engagement with the valve face 68 inthe boss II. This position of the element is taken whenever there is aloss of pressure in the distributing line communicating with the bossll. With the element 12 in its dotted line position, further loss offluid is prevented so as to maintain the remainder of the braking systemin normal operating condition.

The maximum amount of liquid that can be distributed through a multipleconnection cannot exceed the amount which may be delivered to thesmallest cross sectional area of the conduit supplying thedistributingconnection. Therefore in order to distribute this maximum amount throughthe outlets of the multiple connection, the total area of the outletsneed not exceed the smallest area of the inlet or supply.

Regardless of the number of outlets in a dis.- tributing connector, thetotal or maximum quantity that may be delivered cannot be greater thanthe amount supplied to the connector or point of distribution.Accordingly the amount of liquid at the bosses l6 and .II would not begreater thanthat supplied through the boss l2.

Since the amount of fluid at the distributing outlets is not greaterthan that admitted on the inlet side and the total cross sectional areaof the ports I. is less than the smallest cross sectional area on theinlet side, the volumetric capacity of the outlet sides is greater thanthe capacity of the ports 50. By the reduction of the ports ll, areserve of liquid and pressure is built up in the ports and back to thesource of supply, which is employed in unseating the element 12. Thepressure in the small ports 88 is equal at all times in a normal systemand when a break occurs, the pressure on the side of the break beyondthe small port I! on that side is reduced, but the pressure on theunbroken side is maintained at that of the small port It on that side ofthe outlet. This higher pressure on the unbroken side moves the elementI2 01! its seat and into engagement with the seat I on the broken or lowpressure side, thus preventing loss of fluid on the broken side butpermitting operating pressure to be maintained on the unbroken side. Therubber washer 62 on the broken side holds the element 12 against theseat 68 when the pressure on the element is reduced.

Without further elaboration, the foregoing will so fully explain myinvention, that others may, by applying current knowledge, readily adaptthe same for the use under various conditions of service.

I claim:

In a valve for a fluid distributing system, a body having an elongatedcylindrical chamber centrally thereof and co-axial with an outletpassage at each end, said body also having an inlet passageperpendicular to the medial portion of the chamber, a partition flxed inthe inner end of the inlet passage having a pair of transversely spacedinlet ports the diameter of each of said ports being appreciably lessthan the smallest diameter of the inlet passage or either of the outletpassages, a ball valve mounted in the passage and normally disposed insubstantially sealing contact with the partition between its ports, anadjustable spring pressed member having a concaved inner end resilientlyengaging the ball to releasably hold the same in its normal centerposition, a seat in each outlet passage adapted to receive the ballvalve upon reduction of pressure in the respective passage, andcompressed resilient meansfor holding the valve in either'of its seatedpositions to close one of said outlet passages there being a roundedannular part on each of said means slightlyprojecting into each of saidoutlet passages.

RUDOLPH H. BLANK.

